The following are pre-publication drafts of articles from the Morbidity and Mortality Weekly Report dated September 8, 1995. Late-breaking articles, and final editorial revisions are not included; therefore, these articles should be considered preliminary, and not to be released to the public. --CDC -------------------------------------------------------------- Arboviral Disease -- United States, 1994 Arboviruses are mosquitoborne and tickborne agents that persist in nature in complex cycles involving birds and mammals, including humans. Characteristics of arboviral infection include fever, headache, encephalitis, and sometimes death. In 1994, health departments in 20 states reported 100 presumptive or confirmed human cases of arboviral disease* to CDC. Of these, 76 were California (CAL) serogroup encephalitis; 20, St. Louis encephalitis (SLE); two, western equine encephalomyelitis (WEE); one, eastern equine encephalomyelitis (EEE); and one, Powassan encephalitis (POW). This report summarizes information about arboviral disease in the United States during 1994. Powassan Encephalitis POW was serologically confirmed in a 49-year-old female resident of Massachusetts who had onset of illness May 24. She reported removing an engorged tick from her abdomen approximately 2 weeks before onset of symptoms. She was admitted to the hospital on May 25 with a diagnosis of meningoencephalitis, which progressed during the following 72 hours to encephalitis involving the brain stem and basal ganglia. During hospitalization, the patient was comatose for 3 days and required mechanical ventilation. On June 16, she was discharged to a rehabilitation center and, on July 25, was transferred to a resident health-care facility. On examination in August 1995, she had residual weakness in her right leg requiring a brace. The patient's prolonged convalescence is consistent with that reported for POW encephalitis. California Serogroup Encephalitis During 1994, a total of 76 human CAL serogroup encephalitis cases were reported from 13 states: West Virginia (32 cases), Ohio (14), Wisconsin (seven), Illinois (six), Minnesota (four), Indiana and North Carolina (three each), Alabama (two), and Iowa, Kentucky, Michigan, Rhode Island, and Virginia (one each). Patients ranged in age from 6 months to 26 years (mean: 7 years). A total of 57 cases (75%) occurred among males. Onsets of illness occurred in May (one case), June (one), July (12), August (35), September (22), and October (five). St. Louis Encephalitis During 1994, a total of 20 human cases of SLE were reported from five states. Sixteen cases were reported in Louisiana; most (14) occurred in urban New Orleans (Orleans and Jefferson parishes). Three cases (in 44- and 60-year-old men and a 63-year-old woman) were fatal. Patients ranged in age from 12 to 78 years (mean: 46 years). Of the 16 cases, nine (56%) occurred among males. SLE cases also were reported in residents of Riverside County, California; Charlotte County, Florida; Forrest County, Mississippi; and Harris County, Texas (one each). For the 20 total cases, onsets of illness occurred in July (one case), August (nine), September (nine), and October (one). Western and Eastern Equine Encephalomyelitis During 1994, two human cases of WEE were reported from Goshen County in southeastern Wyoming; the cases occurred in a 40-year-old woman and a 42-year-old man. One human case of EEE in a 67-year-old man was reported from Iberville Parish, Louisiana. Western and Eastern Equine Encephalomyelitis in Animals Surveillance for arboviral disease includes cases in susceptible animals because, during previous outbreaks, animal cases preceded human cases by 2-3 weeks. During 1994, a total of five WEE cases among horses were reported from three states: Idaho (two cases), Wyoming (two), and Texas (one). WEE was isolated from emus in Boulder County, Colorado (one), and Lancaster County, Nebraska (one), and from a symptomatic pigeon in Stanislaus County, California. A total of 133 cases of EEE among horses were reported from 11 states: Florida (54 cases), South Carolina (20), North Carolina (15), Michigan (12), Georgia (nine), Alabama and New Jersey (seven each), Indiana and Louisiana (three each), Ohio (two), and Virginia (one). In addition, EEE virus was isolated from other species in five states. In Michigan, virus was isolated from two pheasant flocks. In Florida, EEE virus was isolated from specimens of viscera from a symptomatic duck and from 1-4-week-old piglets during an epizootic in the Florida panhandle in which 50 of 90 piglets observed had objective central nervous system signs; the number of deaths is unknown. In Georgia, EEE virus was recovered from a litter of 3-week-old boxer puppies; three of five puppies in the litter died. EEE cases in emus were reported from New Jersey (10 cases), Florida (three), Georgia (two), and North Carolina (one). Reported by: State health depts. D Jacoby, MD, Massachusetts General Hospital, Boston. M McGuilf, DVM, Epidemiology Div, J Fontana, MS, B Werner, PhD, Virology Div, Massachusetts Dept of Public Health State Laboratory. L McFarland, DrPH, S Wilson, M Kohn, MD, H Bradford, PhD, Louisiana Dept Health and Hospitals; E Bordes, New Orleans Mosquito Control Board, New Orleans. D Alstad, DVM, National Veterinary Svcs Laboratories, Animal Plant and Health Inspection Svc, US Dept of Agriculture, Ames, Iowa. H Rubin, DVM, Bur of Diagnostic Laboratories, Florida Dept of Agriculture and Consumer Svcs, Kissimmee. S Baldwin, DVM, Veterinary Diagnostic and Investigation Laboratory, Univ of Georgia, Tifton. Epidemiology and Ecology Section, Div of Vector-Borne Infectious Diseases, National Center for Infectious Diseases, CDC. Editorial Note: The findings in this report indicate that CAL serogroup encephalitis remains the most frequently reported arbovirus infection in the United States. Although the number of CAL serogroup encephalitis cases has remained relatively constant since the 1970s and was reported primarily from the Midwest, the number of cases reported from the South has increased. For example, in 1994, Alabama for the first time reported CAL serogroup encephalitis cases, and Kentucky and Virginia--which previously had reported a total of only six cases since 1964--each reported one in 1994. In general, SLE occurs as periodic focal outbreaks followed by years of sporadic cases. In 1994, a small focal outbreak of SLE occurred in urban New Orleans. Evaluation of case-patients by date of illness onset and location suggests that the earliest cases occurred among persons living within or in proximity to urban public housing projects. Subsequent cases followed a pattern of radial spread from the central urban area, although the small number of cases preclude a definitive analysis. An investigation by New Orleans Mosquito Control Board personnel found large populations of immature and adult Culex pipiens quinquefasciatus mosquitoes under housing units. Leaking sewer lines located in the crawl space beneath these housing units provided an extensive and ideal habitat for the SLE virus vector mosquito. The POW case in Massachusetts in 1994 was the first reported from that state. Previously, the most recent POW case in the United States occurred in New York in 1978. POW virus is a tickborne flavivirus most closely related to Russian spring summer and Central European encephalitis viruses. Although understanding of the epidemiology of POW virus in the United States is limited, the virus appears to be widely distributed. In North America, Ixodes cookei has been implicated as the principal tick vector, and virus has been recovered from several rodent and carnivore species, including the red squirrel, woodchucks, striped and spotted skunks, foxes, short- and long-tailed weasels, and the white-footed deer mouse.** Human infections with POW virus occur infrequently, with seroprevalence rates of 0.5%-4.0% in areas where the virus is endemic (1). During 1958-1981, a total of 19 confirmed POW cases among humans were reported in North America, primarily from the northeastern United States and eastern Canada. Since 1981, five additional confirmed cases have been reported from Canada: Quebec (two, one fatal) (H. Artsob, Quebec Laboratory Center for Disease Control, personal communication, 1995); New Brunswick (one) (2); Ontario (one); and Nova Scotia (one) (M. Mahdy, Ontario Ministry of Health Laboratory Services, personal communication, 1995). Based on evaluation of the 24 total POW cases that occurred in North America during 1958-1994, risk for infection may be highest in wooded areas where potential contact with infected rodent or carnivore hosts or tick vectors is greatest. Of the 24 cases, 21 occurred in persons aged less than 20 years. Four of the acute infections were fatal, and two patients died 1 and 3 years after onset as a result of sequelae reported to be directly related to the disease. Health-care providers should consider arboviruses in the differential diagnosis of aseptic meningitis and encephalitis cases during the summer months. Early identification of arboviral cases is important to implement risk-reduction strategies (i.e., use of vector-control practices, repellents, and changes in human activity patterns). Serum (acute and convalescent) and cerebrospinal fluid samples should be obtained for serologic testing, and cases should be promptly reported to state health departments. New rapid diagnostic techniques, including detection of immunoglobulin M antibody in acute serum or cerebrospinal fluids, have facilitated confirmation of arbovirus infections. References 1. Artsob H. Powassan encephalitis. In: TP Monath, ed. The arboviruses: epidemiology and ecology. Vol IV. Boca Raton, Florida: CRC Press, Inc, 1988:29-49. 2. Fitch W, Artsob H. Powassan encephalitis in New Brunswick. Can Fam Physician 1990;33:1289-90. * At CDC, a confirmed case is defined as febrile illness with mild neurologic symptoms, aseptic meningitis, or encephalitis with onset during a period when arbovirus transmission is likely to occur, plus at least one of the following criteria: 1) fourfold or greater rise in serum antibody titer, 2) viral isolation from tissue, blood, or cerebrospinal fluid; or 3) specific immunoglobulin M (IgM) antibody in cerebrospinal fluid. A presumptive case is defined as compatible illness, plus either a stable elevated antibody titer to an arbovirus ( greater than or equal to 320 by hemagglutination inhibition, greater than or equal to 128 by complement fixation, greater than or equal to 256 by immunofluorescent assay, or greater than or equal to 160 by plaque-reduction neutralization test) or specific IgM antibody in serum by enzyme immunoassay. ** Tamiasciurus hudsonicus, Marmota monax and Mephitis mephitis, Spilogale putorius, Vulpes sp. Urocyon Cinereoargenteus (gray fox), Mustella erminea and Mustella frenata, and Peromyscus maniculatus, respectively. Update: Influenza Activity -- Worldwide, 1995 From October 1994 through August 1995, influenza activity occurred at low to moderate levels in most parts of the world. Influenza activity usually was associated with the cocirculation of influenza types A and B viruses. Overall, influenza A(H3N2) was the predominant influenza A subtype, but isolation of influenza A(H1N1) viruses increased during this period and was the most frequently isolated influenza virus in Australia from March through August. This report summarizes influenza activity worldwide from March through August 1995. Africa. In Madagascar, circulation of influenza A(H3N2) began during January and continued through April; during April, influenza A(H1N1) was isolated in Madagascar. In South Africa, influenza A(H1N1) and influenza A(H3N2) viruses were isolated from samples collected for respiratory virus isolation during May-July. Influenza B viruses also were detected in South Africa during July. Influenza A(H3N2) was isolated in Zambia during June. Asia. Influenza A(H1N1), A(H3N2), and influenza B viruses were isolated during every month from March through June in Asia. Influenza A(H1N1) viruses were isolated in Guam during May, in Hong Kong during March and April, and in Thailand during April, May, and July. Influenza A(H1N1) and influenza B viruses were isolated during outbreak-level activity in Taiwan during April-June. Other countries reporting influenza B activity associated with sporadic cases or outbreaks included China, Hong Kong, Japan, Korea, Singapore, and Thailand. Influenza A(H3N2) viruses were isolated in China in association with sporadic and outbreak activity during April and from sporadic cases during June. Influenza A(H3N2) viruses also were isolated in Korea and Thailand during March, in Guam during March and May, in Hong Kong during March and July, and in Japan during April. Singapore reported influenza A activity every month from March through June; influenza A (H3N2) isolates were subtyped during March, May, and June. Additional influenza A viruses, subtype unknown, were identified by antigen-detection methods in Malaysia during March. Europe. Activity in Europe began with an outbreak of influenza B virus in Portugal during October 1994 and continued from March through June. Influenza A(H3N2), A(H1N1), and influenza B viruses were isolated during this period. Outbreak activity was last reported from Romania and Bulgaria during May. Circulation of influenza A(H1N1) viruses increased from March through May and was associated with an outbreak in members of a military unit in Bulgaria. Detection of both influenza A and influenza B viruses continued in France during June. North America. Influenza A(H3N2) viruses predominated during the 1994-95 season, but influenza B and A(H1N1) viruses also were isolated. Following peak activity during February through early March in the United States, influenza A(H3N2), A(H1N1), and influenza B viruses continued to be isolated every month during March-June. Influenza A(H1N1) was isolated from one patient in Arizona during July. The number of influenza A(H1N1) isolates increased during February-May; most were collected during May. Late-season influenza activity also occurred in Canada. The most recent detection of influenza B virus was reported during the week ending June 3, and reports of influenza A virus isolation or detection continued during July and August. As in the United States, influenza A(H1N1) viruses were reported in Canada during the latter part of the influenza season. Central and South America. Influenza A and influenza B viruses were detected during the 1994-95 influenza season in South America with influenza A predominating. Brazil reported detection of influenza A from February through April. In Chile, outbreaks of influenza were detected during May-July; influenza A predominated, but influenza B also was detected. In Argentina, the first case of influenza A was diagnosed in late May and outbreaks were reported during June and July; influenza A predominated, but influenza B also was detected. Reports of influenza-like illness increased in Uruguay during May-July, and influenza A virus was identified by antigen-detection methods. Influenza A virus was detected in one patient in Panama during June, followed by a single detection of influenza B virus during July. All influenza A viruses from Argentina, Brazil, and Chile subtyped or further identified by serologic testing were influenza A(H3N2). No influenza A(H1N1) isolates were reported from Central or South America. Oceania. The influenza season began early in Australia with outbreaks in the Northern Territory at the end of March. Both influenza A(H1N1) and influenza B viruses were isolated during the outbreak, with influenza A(H1N1) viruses predominating. Influenza-like illness, as reported by general practitioners, increased through the beginning of July and remained stable during mid-July through the beginning of August. As the season progressed, the number of influenza B isolates increased; however, influenza A(H1N1) viruses remained more prevalent. Influenza A(H3N2) viruses were rarely isolated. In contrast, influenza B predominated in New Zealand through July, but the proportion of influenza A(H3N2) viruses isolated increased during July. Both influenza A(H3N2) and influenza B viruses were associated with outbreaks at the end of July. Characterization of influenza virus isolates. From October 1, 1994, through August 15, 1995, a total of 760 influenza isolates collected worldwide were antigenically characterized by the World Health Organization Collaborating Center for Surveillance, Epidemiology, and Control of Influenza at CDC. Of these, 535 (70%) were from North America, 76 (10%) from Europe, 130 (17%) from Asia, and 19 (3%) from South America and Oceania. Of the viruses subtyped, 396 (52%) were influenza A(H3N2), 91 (12%) A(H1N1), and 273 (36%) influenza B. Of the 396 influenza A(H3N2) isolates characterized, 227 (57%) were antigenically related to A/Shangdong/09/93, the 1994-95 vaccine strain, and 164 (41%) were more closely related to A/Johannesburg/33/94, the A(H3N2) component of the 1995-96 influenza vaccine. Of the 273 influenza B viruses, 66 (24%) were similar to B/Panama/45/90, the 1994-95 vaccine component, and 202 (74%) were similar to B/Beijing/184/93, the 1995-96 vaccine component. Of the 91 influenza A(H1N1) viruses, 12 (13%) were A/Texas/36/91-like, and 79 (87%) were more closely related to the antigenically similar A/Taiwan/01/86-like viruses (1,2). The influenza A(H1N1) component of the 1995-96 vaccine is A/Texas/36/91. Reported by: World Health Organization National Influenza Centers, Communicable Disease Div, World Health Organization, Geneva. World Health Organization Collaborating Center for Surveillance, Epidemiology, and Control of Influenza. Influenza Br, Div of Viral and Rickettsial Diseases, National Center for Infectious Diseases, CDC. Editorial Note: Based on recent patterns of worldwide influenza activity, the 1995-96 influenza season in the United States may be characterized by cocirculation of influenza type A(H3N2), type A(H1N1) and type B. However, because specific patterns of influenza activity cannot be predicted with certainty, the extent of virus circulation and the relative prevalence of the different influenza virus strains is unknown. Therefore, influenza vaccination should be offered each fall to persons at high risk for influenza-related complications and their close contacts and to health-care providers. The influenza vaccine is updated annually to include viruses that are antigenically similar to the strains of the three distinct groups of influenza viruses that have been in worldwide circulation. Most of the influenza viruses isolated since March 1995 are antigenically similar to the 1995-96 influenza vaccine strains (CDC, unpublished data, 1995). Vaccination against influenza is recommended by the Advisory Committee on Immunization Practices for 1) persons aged greater than or equal to 65 years; 2) persons who reside in nursing homes or chronic-care facilities; 3) persons with chronic cardiovascular or pulmonary disorders, including children with asthma; 4) persons who required medical follow-up or hospitalization during the previous year because of diabetes and other chronic metabolic diseases, renal dysfunction, hemoglobinopathies, or immunosuppression; and 5) children and adolescents who are receiving long-term aspirin therapy and who therefore may be at risk for developing Reye syndrome after influenza. Vaccination also is recommended for health-care workers and other persons who are in close contact with persons in high-risk groups, including household members. Women who will be in the third trimester of pregnancy during the influenza season may be at increased risk for medical complications following influenza infection and should consult with their health-care providers about receiving the vaccine. Influenza vaccine also can be administered to anyone who wants to reduce the likelihood of acquiring influenza. Beginning in September, persons at high risk who are seen by health-care providers for routine care or as a result of hospitalization should be offered influenza vaccine. The optimal time for organized vaccination campaigns is mid-October through mid-November. Health-care providers should continue to offer vaccine to high-risk persons up to and even after influenza activity is documented in a community. Information about influenza surveillance is available through the CDC Voice Information System (influenza update) by telephone ([404] 332-4555) or fax ([404] 332-4565) (document number 361100) or through the CDC Information Service on the Public Health Network electronic bulletin board. From October through May, the information is updated weekly. Periodic updates about influenza are published in MMWR, and information on local influenza activity is available through county and state health departments. References 1. CDC. Update: influenza activity--United States and worldwide, 1993-94 season, and composition of the 1994-95 vaccine. MMWR 1994;44:179-83. 2. CDC. Update: influenza activity--United States and worldwide, 1994-95 season, and composition of the 1995-96 vaccine. MMWR 1995;44:292-5. Notice to Readers NIOSH Alert: Request for Assistance in Preventing Deaths and Injuries of Adolescent Workers CDC's National Institute for Occupational Safety and Health (NIOSH) periodically issues alerts about workplace hazards that have caused death, serious injury, or illness in workers. One such alert, Request for Assistance in Preventing Deaths and Injuries of Adolescent Workers (1), was recently published and is available to the public.* This alert summarizes information about work-related injuries and deaths among adolescents, identifies work that is especially hazardous, and offers recommendations for prevention. This information can help employers, parents, educators, and adolescent workers make informed decisions about safe work and recognize hazards in the workplace. Each year, approximately 70 adolescents die from injuries at work. Hundreds more are hospitalized, and tens of thousands require treatment in hospital emergency departments. For example, 68 adolescents aged less than 18 years died from work-related injuries in 1993 (2), and an estimated 64,000 adolescents had work-related injuries that required treatment in hospital emergency departments in 1992 (3). Compared with adults, adolescents have a higher risk for work-related injury (4) and a similar risk for fatal occupational injury (5). During 1980-1989, the risk for fatal injury among workers aged 16 and 17 years was 5.1 per 100,000 full-time equivalent workers, compared with 6.0 for adult workers--even though adolescents are employed less frequently in especially hazardous jobs. Agricultural businesses and retail trade accounted for the most work-related deaths among adolescents, and many deaths of workers aged less than 16 years occurred in family-owned businesses (1). Types of work associated with large numbers of deaths and serious injuries included the following: working in or around motor vehicles, operating tractors and other heavy equipment, working near electrical hazards, working in retail and service businesses with a risk for robbery-related homicide, working with fall hazards such as ladders and scaffolds, working around cooking appliances, and performing hazardous manual lifting. To reduce the potential for serious injuries and deaths of adolescent workers, NIOSH recommends: 1. Employers should know and comply with child labor laws and should evaluate workplace hazards for adolescent workers. 2. Parents should participate in their children's employment decisions and should discuss the types of work, training, and supervision provided by the employer. 3. Educators should know child labor laws, provide work experience programs with safe and healthful work environments, and incorporate occupational safety and health information in the general curriculum. 4. Adolescents should know their rights and responsibilities as workers and should seek training and information about safe work practices. References 1. NIOSH. Request for assistance in preventing deaths and injuries of adolescent workers. Cincinnati: US Department of Health and Human Services, Public Health Service, CDC, 1995; DHHS publication no. (NIOSH)95-125. 2. Toscano G, Windau J. The changing character of fatal work injuries. Monthly Labor Review 1994;118:17-28. 3. Layne LA, Castillo DN, Stout N, Cutlip P. Adolescent occupational injuries requiring hospital emergency department treatment: a nationally representative sample. Am J Public Health 1994;84:657-60. 4. CDC. Surveillance of occupational injuries treated in hospital emergency departments. MMWR 1983;32 (no. 2SS):31SS-37SS. 5. Castillo DN, Landen DD, Layne LA. Occupational injury deaths of 16- and 17-year-olds in the United States. Am J Public Health 1994;84:646-9. * Single copies of this document are available without charge from the Publications Office, NIOSH, CDC, Mailstop C-13, 4676 Columbia Parkway, Cincinnati, OH 45226-1998; telephone (800) 356-4674 ([513] 533-8328 for persons outside the United States); fax (513) 533-8573. Errata: Vol. 44, No. 32 In the article, "Human Granulocytic Ehrlichiosis--New York, 1995," references 4,5, and 3 at the end of the second and third sentences of the Editorial Note on page 594 should be renumbered (3,4) and (5), respectively; however, the numbers were attributed to the correct references in the list on the following page. The fourth and new fifth sentences of the first paragraph of the Editorial Note should read: "E. chaffeensis has most commonly been identified in the Lone Star tick (Amblyomma americanum) (6)." HGE patients reported having been bitten by "deer ticks" and "wood ticks" (possibly I. scapularis and Dermacentor variabilis, respectively) (2)." The new reference 6 is: Anderson BE, Sims KG, Olson JG, et al. Amblyomma americanum: a potential vector of human ehrlichiosis. Am J Trop Med Hyg 1993;49:239-44. Erratum: Vol. 44, No. 34 In the article "Hypertension Among Mexican Americans--United States, 1982-1984 and 1988-1991," the last sentence on page 635 should read: "Analysis of characteristics of persons with hypertension included awareness (being told by a health professional of having hypertension), treatment (taking antihypertension medication),and control (taking antihypertension medication and having blood pressure less than 140/90 mm/Hg)." Erratum: Vol. 43, No. 38 On page 702 of the article "Health Status of Displaced Persons Following Civil War--Burundi, December 1993-January 1994," in the "Reported by:" section, S Nkurikiye should be listed first, and the affiliation of JS Kidasi should be U.S. Agency for International Development.